Why does this error occur?
When your computer starts, the system BIOS begins to check a pre-determined list of drives and devices that may contain an operating system (Windows 7 or Windows 8). Normally, the computer boots from your primary hard drive, or a boot device that you have selected, where the operating system is stored. If the boot device is damaged, or if the computer attempts to boot from a different device, the operating system does not start up and you receive an error message. There are numerous possible causes and solutions for this error. Use this document as a guide through the troubleshooting process.How can I fix this error?
Try the following troubleshooting steps, in order, until Windows starts normally.Step 1: Check the computer cable connections
Make sure that all computer cables are connected properly to the correct ports. Check the connections at both ends of each cable. If you recently moved a cable to a different port on the computer, move it back to the original port, if possible. When finished, restart the computer.Step 2: Remove all external devices
Disconnect all peripheral devices from your computer (for example: printers, memory card readers, external hard drives, and external CD/DVD drives), except the keyboard, mouse, and monitor (if applicable). With all devices disconnected, restart the computer. If the computer starts normally, it was attempting to boot from one of the external devices. Reconnect the devices one at a time, restarting each time, to identify which device was causing the problem.Step 3: Select a different boot device
The boot order may have been changed, or a partition was added or removed, causing the computer to attempt to boot from the incorrect device or partition. Reset the default boot order or select a different boot device using the steps in the appropriate section for your computer:

NOTE:BIOS configurations vary depending on the computer model. The BIOS settings are generally found in the Maintenance and Service Guide, available on the HP product page for your computer model.

NOTE:The steps for modifying the boot order can vary depending on the computer model. Use the following steps as a guide while paying attention to the on-screen instructions. Some steps may be slightly different on your computer.